Beyond BMI and Bathroom Scales

Measuring your weight on a scale, and using BMI as your marker of health can give false information if you do not know how to interpret it – an most people do not know how to interpret it. In order to really understand how little useful information BMI and scales give, you need to understand body composition. As we’ve discussed previously, your body is like a house, built with all sorts of different materials. These materials all play a part in how much you weigh. Brick walls weigh more than dry wall. Muscle weighs more than fat. When we step on a scale, that scale is giving us the total weight of our bodies, but It is not telling us how much of that weight is from the fat versus the muscle versus the bone. So the typical bathroom scale, and your weight, cannot on its own tell you how healthy or unhealthy you are.

What does that mean for the average person? Well if you do weight lifting and have a lot of muscle, when you step on the scale you are going to be heavy, because a strong muscular body is like a brick wall, it will be heavy and sturdy, naturally it will weigh more. But does that make the weightlifter unhealthy? The scale says they weigh 230 pounds, but the scale isn’t telling you most of that weight is coming from muscle mass and dense strong bones. What if the same weightlifter, five years ago, did not do weightlifting, was eating unhealthy foods, did not exercise or move much and had a lot of fat on their body. What if the same person, 5 years ago, weighed 230 pounds as well. The scale does not tell them that a lot of that weight 5 years ago was from fat. So does the person on the scale today, the weightlifter, conclude that all their healthy lifestyle changes, their hard work in the gym and the past 5 years mean nothing because they’re the same weight today (230 pounds) as they were 5 years ago when they were living an unhealthy lifestyle?

You need to be smart in interpreting weight, particularly if you are actively trying to be healthier through good nutrition and exercise. If you are exercising, particularly weightlifting, the scale is going to make you think you are not making any progress when in fact you are. Your change in nutrition and your exercise might be completely changing your body composition. You might be reducing fat and increasing your muscle mass. But the scale may not show any difference because the muscle you are gaining still has weight. The scale cannot tell you that the number it is showing comes from a combination of your newly increased muscle mass and what’s left of the fat you are losing. All it gives is a number. If you understand this concept then you are less likely to get discouraged or give up your healthy lifestyle changes and undo all the progress you have done.

A better way to figure out changes in body composition is to get simple measuring tape and measure your waist. Best time is before breakfast since your stomach distends when you eat and then if you get gassy or are retaining water that might add inches (or centimeters for my metric system users). waistcircumference table

The waist circumference measure tells you more about fat loss or health risks than your weight on a scale or even BMI. There are some devices, expensive bathroom scales and hand held devices that use electricity to determine your fat versus muscle body composition. The flaw is the ones you step on only measure the composition in your lower body (mainly legs) and the hand held ones only measure your upper body (arms and torso). The absolute best way to really determine your body composition is also really expensive – the DXA scan. So for practical, affordable home measurement a measuring tape is really all you need. It’s not a perfect estimate, but it’s better and more straightforward than simple weight.

You may sometimes hear health professionals refer to Body Mass Index (BMI) which is a calculation using height against weight to determine whether or not you have an unhealthy amount of fat. However, this little mathematical equation does not actually measure how much fat you have in your body because it is based on the same flawed logic as using weight alone to determine that. It does not consider body composition. So a weightlifter can have the same BMI as an obese person (as in the example earlier). Yet BMI is treated as the best and easiest measure of physical health in healthcare circles when it is gravely flawed. Unfortunately, a lot of health services, especially if they haven’t seen you in person or do not know your lifestyle, will give you advice or information based on your BMI. Taking the time to understand our bodies and body composition, understand cause and effect, understand that health is a multidimensional thing and cannot be determined by a number on a bathroom scale, can go a long way in helping us to make the best choices for ourselves, and to challenge all the misleading information that comes to us from many sides.


© 2016 Kelene Blake, All Rights Reserved